Question: Omar is 5 times as old as Umaima and is also 20 years older than Umaima. How old is Omar?
Solution: We can use the given information to write down two equations that describe the ages of Omar and Umaima. Let Omar's current age be $o$ and Umaima's current age be $u$ $o = 5u$ $o = u + 20$ Now we have two independent equations, and we can solve for our two unknowns. One way to solve for $o$ is to solve the second equation for $u$ and substitute that value into the first equation. Solving our second equation for $u$ , we get: $u = o - 20$ . Substituting this into our first equation, we get the equation: $o = 5$ $(o - 20)$ which combines the information about $o$ from both of our original equations. Simplifying the right side of this equation, we get: $o = 5o - 100$ Solving for $o$ , we get: $4 o = 100$ $o = 25$.